A Femto base station is basically a low cost and low power base station transceiver which is installed indoors (e.g., in a home or office) and connected to the Internet via cable, DSL, on-premise fiber optic link, or a similar IP backhaul technology. This connection is used to integrate the Femto base station with the wireless operator's core network.
A Femto base station serves a geographic area known as a Femtocell over a single carrier or channel. In a wireless network including Femtocells, upon entering a Femtocell, a mobile station receives broadcast overhead messages consistent with well-known standards such as current 3GPP2 CDMA2000 EVDO standards (e.g., 3GPP2 CDMA2000 EVDO standard “cdma2000 High Rate Packet Data Air Interface Specification,” 3GPP2 C.S0024-B, Ver. 2.0 (March 2007)), etc.
When CDMA mobile stations are connected to an IP Multimedia Subsystem (IMS) via a circuit connection (e.g., a CDMA Femtocell) the IMS emulates a Visited Mobile Switching Center (V-MSC)/Visitor Location Register (VLR) in the CDMA mobility network model. In the CDMA mobility network model, the V-MSC/VLR does not have provisioned subscriber data associated with each user that may receive service. Instead, the V-MSC/VLR registers with a Home Location Register (HLR) and dynamically retrieves the subscriber data necessary to provide services for the CDMA users currently served by the V-MSC/VLR.
However, IMS is based on a wireline model, in which case the users of the IMS must be pre-provisioned as subscribers on the IMS before they are allowed even basic access. The conflict between the provisioning strategies for a CDMA network and IMS becomes an issue when using the IMS as a V-MSC/VLR.
This problem relating to provisioning strategies will also apply to UMTS users connected to UMTS Femtocells.
Conventionally, a solution to the provisioning strategy conflict operates on the assumption that there is a pre-provisioned subscriber record on the IMS for each CDMA user that is authorized access through a given CDMA Femtocell. This is often envisioned as a semi-automated provisioning process based on the placing of a CDMA user on an Access Control List (ACL) or Authorized User List (AUL) associated with each Femtocell. However, this scheme has at least three problems.
A first problem is referred to herein as the “coffeeshop” or “public” Femtocell that does not have an ACL of users allowed access. In this case, given that there is no ACL generated for the Femtocell, there is no way of triggering the HSS population of an IMS subscriber record for the CDMA users of such a coffeeshop or public Femtocell.
Another problem is that service providers conventionally have provided feedback that the per-user IMS subscriber record is not acceptable to them. Service providers want the Femtocell system to be able to operate with dynamic data (e.g., just the VLR download) and not be dependent on any per-user pre-provisioned data.
Still another problem is that a pre-provisioning solution generally requires access to the CDMA users' CDMA service provider back office provisioning systems. Because service providers do not allow other service providers to access their back-office provisioning systems, there is a problem supporting CDMA users from another service provider on a Femtocell served by a particular service provider. For example, if a given Femtocell is connected to a Verizon Wireless IMS and back-office system network, it will not be possible for Sprint or Alltel users to get service on that Femtocell because the pre-provisioning process will be blocked due to inability to access the Sprint or Alltel back-office provisioning systems from the Verizon system.